PARIS — Valérie Trierweiler once called Ségolène Royal “the crazy woman of Poitou” and asked members of her partner’s communication team to keep them at arm’s length.

The two women — Ms. Trierweiler is the current partner of President François Hollande of France, and Ms. Royal is his former partner and the mother of his four children — are depicted in three recently published books as fierce rivals, and their animosity has been at the center of extensive news media attention in France this summer.

Since 2007, when Nicolas Sarkozy took office as president in the middle of a marital breakdown, French politics has taken on aspects of a television soap opera, complete with shifting couples and strained relationships. The most recent example adds spice to a mix that was also stirred by accusations of sexual misconduct against Dominique Strauss-Kahn, who wanted to be president.

Recent headlines have included “The Poison of Jealousy” on the cover of the weekly L’Express and “Secrets of a Trio from Hell,” in the left-wing magazine Marianne.

The current wave of coverage started with a Twitter message. During the legislative campaign in the spring, Ms. Trierweiler, 47, angered at Mr. Hollande’s public support for Ms. Royal, sent a message effectively endorsing Ms. Royal’s opponent. This was doubly embarrassing because Ms. Royal, 58, was the official candidate of the Socialist Party and of Mr. Hollande, also 58. Ms. Royal ended up losing badly, so there was humiliation all around.

Mr. Hollande’s amorous life, and his decision to leave Ms. Royal for the younger Ms. Trierweiler, was already well ventilated during his successful presidential campaign. But he is facing a potentially more serious political issue now: The apparent intense rivalry between the women — with Ms. Trierweiler aggressively defending her new position as first partner — may have a slowly degrading effect on his self-styled image as a “normal man” who is now a “normal president.”

The personal strains “first reinforced his image of a normal man who struggled with his private life,” said Érik Emptaz, the chief editor of the satirical weekly newspaper Le Canard Enchaîné. But the coverage has shifted, he said. “Now the impact is on Ms. Trierweiler, who became the nasty one.”

Having trouble with one’s love life is normal in France, too. Mr. Hollande’s relationship with Ms. Trierweiler, who has drawn controversy for keeping her job with the magazine Paris Match, could create protocol difficulties, but those seem less problematic than the noise surrounding the two most important women of his adult life.

Ms. Trierweiler, a twice-divorced mother of three, is described by a former top editor of Le Monde, Laurent Greilsamer, in his virulent book “La Favorite,” as “unconventional, imperial, amorous, explosive, unpredictable. And clearly dangerous.”

According to another book called “The Ex,” by Sylvain Courage, a journalist with the magazine Le Nouvel Observateur, Ms. Trierweiler asked Manuel Valls, then Mr. Hollande’s campaign chief, to erase pictures and quotations attributed to Ms. Royal from campaign videos shown to members of the Socialist Party. Ms. Royal was the party’s presidential candidate in 2007 and nearly became party leader.

As for Ms. Royal, she is presented as the deceived and humiliated woman, who struggled to stop Mr. Hollande from seeing Ms. Trierweiler. “Don’t get close to François; otherwise you’ll regret it,” Ms. Royal is reported as having told Ms. Trierweiler, in the book “Entre Deux Feux,” or “Between Two Fires,” written by Anna Cabana and Anne Rosencher. They discuss Ms. Trierweiler’s “irrational hatred” of Ms. Royal, who is said to have asked Laurence Masurel, a deputy editor at Paris Match, to stop Ms. Trierweiler from covering the Socialist Party.

In this triangle, Mr. Hollande is depicted as a powerless and undecided lover who cannot choose between the two women in his life. “In 2005 and 2007, one struggled to keep him and the other to bring him back,” Ms. Cabana and Ms. Rosencher wrote.

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The main lines of this story appeared in a biography of Mr. Hollande by Serge Raffy, chief editor of Le Nouvel Observateur, that was published last year. The book, “François Hollande: Itinéraire Secret,” or “Secret Itinerary,” asserts that Mr. Hollande’s affair with Ms. Trierweiler began in 2005 after they had all become friends, and that Ms. Royal tried to stop it. The Hollande-Royal relationship was declared over publicly only after she lost the 2007 presidential elections, but it had actually ended earlier, he wrote.

Mr. Raffy also describes how Ms. Trierweiler prevented Ms. Royal from attending the 2009 funeral of Mr. Hollande’s mother, with whom she and the children had a strong relationship. Ms. Royal did not attend Mr. Hollande’s investiture as president.

Until recently, Ms. Trierweiler was seen as an elegant and strong-willed woman who continued to work as a journalist while supporting her partner. She recently negotiated a deal with Paris Match to contribute book and art reviews and other cultural coverage a few times a month.

The anti-Royal tweet in June changed that perception, and Mr. Hollande made a point, in a television interview on July 14 — Bastille Day — of stating that he had told those close to him to keep their private lives private and to resolve their conflicts away from the news media. At the same time, Mr. Hollande’s oldest son, Thomas, told friends that the children would now keep their distance from Ms. Trierweiler.

Ms. Trierweiler has also been criticized for suing French magazines for printing photographs, taken with long lenses, of her and Mr. Hollande in bathing suits. She argues that the photographs are an invasion of privacy, but they are a common summer feature; Mr. Sarkozy and his wife, Carla Bruni-Sarkozy, were often photographed in the same way.

For some commentators, Mr. Hollande’s complicated family life brought into question his ability to control those around him.

“I doubt that the French really want a normal man as president,” said Serge Hefez, a psychiatrist who wrote a book about Mr. Sarkozy in 2010 called “Sarkoze Obsessionnelle,” or “Obsessive Sarkosis.” “A president is asked to be more rational and a better master of his emotion than a normal man,” Mr. Hefez said.

For Maurice Szafran, chief editor of Marianne, the conflict between Ms. Royal and Ms. Trierweiler has “demolished the image François Hollande had built for himself, his way of behaving and presenting himself to his voter.”

Many commentators also acknowledged that the rules of French journalism have changed since 2007, starting with Mr. Sarkozy’s public divorce and quick remarriage, followed by the arrest of Mr. Strauss-Kahn on charges of sexual assault last year, and now his separation from his wife, Anne Sinclair. French journalists have been more eager to investigate, and speculate in print, about the private lives of politicians.

“The torments of the soul have become one of the keys to understand the official history,” L’Express said in a recent editorial. Mr. Hollande’s love life, it said, “is also our business.”

A version of this article appears in print on September 11, 2012, on Page A4 of the New York edition with the headline: In France, New Chapter in Saga of All the President’s Women. Order Reprints|Today's Paper|Subscribe